Senators Byron Dorgan, a Democrat, and Olympia Snowe, a Republican, introduced the Internet Freedom Preservation Act, which would prevent broadband ISPs billing internet companies for preferential access to end users.

The bill would oblige ISPs to not block, interfere with, discriminate against, impair, or degrade the ability of any person to access, use, send, post, receive or offer any lawful content, application or service made available via the internet.

It would also stop ISPs from charging those that offer services via the internet on the basis of the type of content, applications, or services and from giving affiliated companies preferential treatment.

Dorgan, in a statement, said that kind of behavior, which was touted in public by executives from some of the biggest phone companies over a year ago threatens to derail the democratic nature of the internet.

ISPs would still, if the law passes, be able to block or throttle traffic considered a security or stability risk. They would still be able to block botted machines from sending spam, for example, and would still be able to offer content filtering services.

The net neutrality debate, which raged all last year, has unsurprisingly divided companies based purely on which of them stand to lose or gain money if such laws pass.

The ISPs are against further regulation of their industry, as are their big suppliers, including Cisco Systems Inc, which wants to sell devices that enable precisely the kind of prioritization that the bill would forbid.

On the other side, the big e-commerce companies and web services providers, the kinds of companies the ISPs would love to double-bill, are for regulation. The It’s Our Net coalition, fighting for legislation, comprises dozens of firms, including Amazon, Google, Symantec, eBay and Yahoo.

The bill, which is virtually identical to legislation introduced but never voted on last year, is also supported by Senators Kerry, Boxer, Clinton, Obama, Leahy and Harkin.

Both houses of the US Congress are now controlled by the Democrats, who are more generally inclined than the Republicans to support such types of legislation.